The invention relates to an apparatus at a flat card for cotton, synthetic fibres and the like, wherein at least one stationary carding element comprising a carrying element with at least one clothing element is associated with a clothed roller, for example a cylinder.
Fixed carding elements are increasingly being used in textile machines, especially in roller cards and flat cards. These fixed carding elements consist of a profiled carrier member and clothing strips attached thereto (1 to 3 strips per profiled carrier member). The profiled carrier members for fixed carding elements are currently made in the form of profiled members of extruded aluminum which are enclosed on all sides. In the case of a known apparatus (GB 1 543 334), the carrier element is a hollow profiled member, the cross-sectional shape of which includes an enclosed hollow space. Disregarding the two end faces, the hollow space is completely surrounded over its length by enclosed wall surfaces. The heat produced during the carding process is to a large extent removed by way of the fixed carding elements to the outside, the temperature gradient required for the purpose within the cross-section of the profiled member resulting in deformation of the fixed carding element. The greater that gradient, the greater is the deformation. In the case of profiled member cross-sections which are enclosed on all sides, relatively large temperature gradients occur, giving rise to undesirably large deformations. In addition, the enclosed pockets of air have a disadvantageous effect in the case of those profiled members, causing the profiled members to act like thermal insulation and to raise the temperature level of the cylinder and of adjacent components.
It is an aim of the invention to provide an apparatus of the kind described at the beginning that avoids or mitigates the mentioned disadvantages and especially wherein the carrier element is dimensionally stable in operation even when exposed to heat.